State capacity is a useful idea I learned about recently. It roughly means the capability of a state to carry out its desires. States may want to do several things, but their capabilities to do so are limited by the political, economic, and social structure of the societies in which they operate.

A state with high capacity can get whatever it wants to do done, whether by winning over the will of the people or by crushing it with brute force.

• Examples of high state capacity: Germany, Singapore, China.
• Examples of low state capacity: Afghanistan, Venezuela, Democratic Republic of Congo.